Data suggests this massive planet is composed of diamond.
Scientists at Yale University are claiming that a planet, called 55 Cancri e, which is twice as big as Earth, is literally a diamond planet. The head researcher stated “This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth. The surface is likely covered in graphite and diamond rather than water and granite.”
Discovered in 2004, the planet is eight times as massive as Earth. With its temperature estimated to be 3,000-4,000 degrees fahrenheit, unfortunately, it is not habitable. However, it's said to have suitable conditions for presence of diamonds. The study’s researchers conclude that up to 1/3 of the entire planet is potentially diamond.
Diamonds may be more common in our Universe than what the prices at a jewelry store suggest. The Russian government has declassified their discovery of an enormous diamond deposit that reportedly contains trillions of carats of the precious gem, large enough to satisfy markets' demand for 3000 years.
While the government has known about the contents of the site below a 62 mile asteroid crater in eastern Siberia since the 1970s, the information was disclosed only recently.